Dyking fibrous materials with tat



Patented Se t. 26, 1 939 UNITED STATES PATENT OFFICE,

lands, assignor to J. A. Carps Garentabrieken N. V., Hclmond. Netherlands,- a corporation of the Netherlands No Drawing. Application September 30, 1936, Se rial 103,351. In the Netherlands October 3 Claims. (Cl. 8-34) This invention relates tovdyeing fi rous ma terials with vat dyestuffs.

It is well known that thorough penetration and levelling of the dyeings with vat dyestuffs on fibrous materials, especially yarns and fabrics,

presents great diiiiculties. Attempts have been made in various ways to overcome the said dimculties .and a large number of processes having the object oi. improving the unequal penetration m or levelling power of the dyestufis have been described. -It has, for example, been proposed to add protective colloids to the dye bath or to the material to be dyed, e g. albuminous substances such as glue and gelatine, sulphitecellulose lye, substances such as the product known under the trade name Peregal O and'similar materials. It

is assumed that agents of this character retard m the absorption of the leuco bases of the vat dyestuilsto such an extent. that a more level dyeing eflect is obtained. This method, however. has .the drawback that the dyeing operation takes much time and that the-baths are only very incompletely exhausted.

The amount of dyestufl' remainingin the bath is larger when using protective colloids, than without the same. Moreover the results are not so good that really satisfactory results are obtained, especially when dyeing with light pastel colours.

Another prior process attempts to improve the dyeing by increasing the temperature used in the dyeing operation. In this case it is necessary to bind the hydrosulphite present in the bath by adding aldehydes or ketons. as the hydrosulphite would be decomposed at the temperatures used. However, even in this case the desired thorough penetration and levelling effect is notobtained and the process has the draw- .backthat certain dyestuffs change their colour to someextent at the high dyeing temperature It has also been proposed to meet the dimculties by forcing the dyestuii solution under the 45 pressure of a neutral gasthrough the material to be dyed. but satisfactory results are not obtained'in this way.

. It has further been. proposed to immerse the material according to the so-called sloppad- .ding process" in a suitable non-reduced suspension of the dyestuffs and to develop the same in a-so-called blind vat. In this ,way satisfactorythorough penetration and levelling results are obtained. However, this process is rather flfinbtsbme d requires ry esactworking and dyeing of fibres.

ideal apparatus conditions, and on the whole it can only be used for the very finely divided dyestufls. Moreover the same difliculties as indicated above are encountered when dyeing with light pastel colours.

According to the process of this invention an excellent thorough penetration and levelling is obtained by dyeing the fibrous materials with vat dyestufis by immersing the said materials in an alkaline solution of the leuco base of the dye-. stuff and producing the dyestuii by oxidation in the fibres using a dye bath containing a substance acting as a water soluble organic solvent for the salts of the leuco base of the dyestufl in an amount which is large with respect to the amount of dyestufi used.

The alkaline solutions referred to above generally contain salts of the leuco bases with inorganic bases, preferably sodium, but they may also contain salts of organic bases.

The effect of the addition of the said solvents of dispersion .of the salts of the leuco bases. It

is well known that the degree of dispersion of the dyestufi's is a very important factor in the If the degree of dispersion is too high as, for example, in the case of the acid and basic dyestuils which are dissolved in almost molecular form, the material does not take up an appreciable amount of dyestuff. If the degree oi dispersion is too low the adsorption. of the dyestufl's is too strong so that they are desposited at the surface of the material in an irregular manner. V In order to obtain satisfactory dyeing conditions the dyestufis therefore should have a degree of dispersion lying between that of purely colloidal and of molecular dispersions. This condition is generally satisfied by the substantive dyestufiswhereas the soluble salts of the, leuco bases of vat dyestuffs are probably in the range of too low degree of dispersion. The favourable effect-of the addition of water soluble organic solvents for the salts of the leuco bases of the vat dyestufis can probably be explained in this way that they increase the degree of dispersion operation. The solutions of the salts of the leuco bases in water have a colloidal character whereas the solutions in certain organic solvents are more or less molecular solutions so that by controlling the relative proportions of water and theor-j ganic solvent the desired degree of dispersion of the dyestuif can be obtained.

The number of organic solvents suitable for the purpose of the invention is rather limited. In the first place they must be soluble, preferably miscible in all proportions with water. Furthermore it is obviously unsuitable to use substances which react with the reduction agents used in the dyeing process so as to form inactive substances. Neither can substances be used which combine with the alkali present in the bath. For practical purposes the cost of the substance to be used will also have to be considered, and it is very important whether this substance can be recovered from the dyeing bath used in an inexpensive way.

I have found that the water soluble lower alcohols are very suitable for the purpose of the invention, and in order to be sufliciently soluble in water they do not in general contain more than five carbon atoms in the molecule. I preferably use alcohols with a boiling point below that of water, as alcohols of this character can be re' The use of dye baths containing alcohol has also the advantage that the wetting power of the same is substantially increased so that the dyestuffs, either in the form of a paste or of a powder, can be incorporated into the dye bath without a previous treatment with a wetting agent. At the same time it is unnecessary in most cases to subject the materials to be dyed to a scouring process or other preliminary treatment prior to the dyeing process.

The process according to the invention can be carried out in various ways for example:

1. The material to be dyed is immersed for some time in the concentrated e.v g. aqueousalcoholic solution of an alkali salt of the leuco base; the solution is now diluted with water to the usual concentration so that the degree of dispersion is reduced, and this solution is. used for the dyeing in the usual way.

2. The material to be dyed is immersed for some time in the concentrated, e. g. aqueousalcoholic solution of an alkalisalt of the leuco base, thoroughly squeezed, washed and further treated in the usual way. The bath can be restored to the original volume and the original concentration by adding a concentrated aqueousalcoholi'c solution of the leuco base of a suitable concentration, and the bath can then be used again for dyeing fresh material. In this'way we can proceed until the amount of impurities remaining in the bath becomes too large.

However, there are also vat dyestuffs which when using the last mentioned method are absorbed after a shortimmersing period to such an cross wound bobbins or on the weavers beam or by the packing system in which the bobbins are arranged in piles and the dye liquor is caused to circulate through the pile of bobbins. We may also treat yarns in skeins according to the "two bath developing system known for dyeing with Naphtol A. S. dyestuffs.

Furthermore the process according to the invention has considerable advantages when dyeing in the piece in the jigger or other apparatus.

In all the above' mentioned cases a very, satisfactory thorough penetration and levelling effect is obtained and generally the time necessary for the process is considerably shortened so that the costs of labour of the dyeing operation proper are materially reduced.

The invention will be illustrated by the following examples in which the fibrous material used is 54/3 mercerised gassed Sakellaridis yarns with turns per inch. The amount of yarn used in the examples is 5.5 kgms. The colors given hereinafter are those found in the work "Schultz Farbstoiftabellen 7th edition, and references will therefore be made in each case to volume and page.

1. A bath of the following composition is prepared:

Distilled water; litres 10 Methylated spirit do 10 Caustic soda (38 B6.) do 1 2 Sodium hydrosulphite grams 400 To this mixture is added 110 grams of Indanthrene Brilliant violet R. R. Powder (Vol. I, page 1265) and the dyestuff is reduced at a temperapared:

' Distilled water litres 10 Methylated spirit do 10 Caustic soda (38 Be.) do 0. 5 Sodium hydrosulphite grams 200 -To this bath is added 5.5 gms. of Indanthrene Brilliant violet R. R. Powder (Vol. I. P e 1265) and the dyestuff is reduced at a temperature of to C. The yarn which has not been subjected to a preliminary treatment is immersed in the solution, thoroughly squeezed and washed, and subsequently treated in the usual way. After the dyeing process the bath'is exhausted to a large extent.

.3. A bath of the following composition is prepared:

Distilled water; litres 10 Methylated spirit do 10 Caustic soda (38 B.) do 0.4 Sodium hydrosulphite; grams 406 To this bath is added 110 gms. of Indanthrene Blue R. S. N. Powder (Vol. I. page 1228) and the dyestui! is reduced at a temperature of -55 to 60 C. The yarn which has been scoured or previous- 1y wetted is immersed in the dyestuff solution for a period of 30 minutes. The solution is diluted to 100 litres with distilled water having a temperature of 55 C. and 1 hem. of sodium 1 drosulphite and 0.8 litre ofa caustic soda solution of 38 B. are added. The yarn is dyed with this dilute bath for some minutes and further treated in the usual way.

4. A bath of the following composition is-prepared:

Distilled water -iitres l 19 Methyiated spirit do.. 10 Caustic soda (38 B.) ....do.. 0.5 Sodiumhydrosulphite -grams 400 To this bath is added 110 gm. of Indanthrene Brown G. Powder (Vol.1, page 1219) and the dyestufl isreduced at a temperature of 50 C. The yarn which has not been subjected to a prelim,- inary treatment is immersed in the liquid for a period 01' 36 minutes, thoroughly squeezed and washed and further treated in the usual way.

. The bath is exhausted to a large extent.

5. A bath of the following composition is Drepared: -Distilled water litres 10 Methylated spirit -do.. 10 Caustic soda (38 Be.) do 0.5 Sodium hydrosulphite grams.i 400 page 1345) and the dyestuif is reduced at a tem- To this bath is added 110 gms. of Indanthrene Brilliantrosa R. Powder (Ciba Red B) (Vol. I,

perature of C. The yarn which has not been subjected to a preliminary treatment is immersed in the liquid for a period of 30 minutes. thoroughly squeezed and washed and further treated in the usual way. The bath is exhausted to a large extent.

6. Two baths of the following composition arev prepared:

Distilled water "litres-.. 15 Methylated spirit do 5 Caustic soda (38 Be.) do., 1.2 Sodium hydrosuiphite grams 400 To each of the said baths is added 400 sins. of Indanthrene'Olive green B. Powder (Vol. 11. page 131) and the dyestuif is reduced at a temperature of 55 C. One of the baths is used as "first bath",

the other as after bath.

5.5 kgms. of the yarn which has been previously scoured or wetted out is immersed in the filrst bath for 2 minutes and pressed together. The

the "first bath; the combined bath is used for" yarn is-subsequently squeezed, washed and fur-- ther treated in the usual way.

One half of the after bath is now added to dyeing 5.5 kgms. of fresh yarn.

The other half of the "after" bath is then added to'the "flrst bath and the mixture is 'used for treating again 5.5 kgms. of fresh yarn.

7. A bath of the following composition is prepared: I I

Distilled water litres 13 Acetamide kgms 10 Caustic soda (38-B.) iitres 1.2

Hydrosulphite -grams 400 To this bath we add 110 gms. of Indanthrene Brilliant violet R. R. Powder (Vol. I, page 1265) and the dyestui'f is reduced .at a temperature of 53" C. The yarn which has been previously treated with a wetting agent is immersed in the liquid for a periodof 15 minutes. The solution is diluted to a volume of litres with distilled water having a temperature of 55 C. and 1 kgm. of hydrosulphite is added. The yarn is dyed for a period of 25 minutes and further treated in the 8. A bath of the ngcomigosition is prepared:

Distilled water -Jitres-.. 10' Isopropyl alcohol (propanol-2) do 10 Caustic soda (38 B.) do 1.2 Sodium hydrosulphite grams 400 To this bath is added gms. or Brilliant violet R. R. Powder (Vol. 1, page 1265) and the dyestuf! Distilled water .litres '10 Acetonedo 10 Caustic soda (36' Be.) ---do 1.2 Sodium hydrosulphite grams 400 To this bath is added 110 gms. of Brilliant violet RR Powder (Vol. 1, page 1265) and the dyestui! is reduced at a temperature of 55 C. The yarn which has been previously treated with a wetting agent is immersed in the bath for a period of 15 minutes. The solution is diluted to 100 litres with distilled water having a temperature of 55 C. and 1 kgm. of hydrosulphite is added. The yarn is dyed during 15 minutes and further treated in the usual way.

10. A bath of the following composition is pre pared:

Distiiled water litres Pyridine do 4 Caustic soda (38 36.) do 1.2 Sodium hydrosulphite grams 400 To this bath is added 110 gms. of Brilliant violet RR Powder (Vol. 1, page 1265) and the dyestufl. is reduced at a temperature of 55 C. The. yarn which hasbeen previously treated with a wetting agent is immersed in the path for a period of 15 minutes. The solution is diluted to 100 litres with distilled water having a temperature of 55 C.

and 1 km. of hydrosulphite'is' added. The yarn is dyed and further treated in the usual way.

For the sake of simplicity the starting material I used in the foregoing examples was the same in all cases. viz. cotton. The process can, however, also be used for other fibrous materials.

11. A bath of the following composition is prepared:

Distilled water litres 20 Methylated spirit ....do 20 Caustic soda (38' Be.) do 0.5 Sodium hydrosulphite grams 400 To this bath is added 200 gms. of Indanthrene Marine blue G Powder (Vol. II. Page 131) and the dyestuff is reduced ata temperature of 55 C. 10 kgms. of viscose artificial silk'bead yarn which has not been subjected to a preliminary treat-' ment is immersed in the liquid for a period of 15 minutes, thoroughly squeezed and washed and further treated in theusual way. The bath is exhausted to a large extent:

vent which is large with respect to the amount of. d y'estuff used" I means that the properties of I organic solvent in the dyeing liquor is a multiple of the proportionof dyestuil, e. g. not less than 5 15 1 By "an amount of water soluble organic soland preferably 10 to 100 times as high and the 'amount of organic solvent, calculated on the aqueous solution is generally not less than 10%.

I claim:

1. A vat process for dyeing fibrous materials with vat dyestufls comprising immersing'the said materials in an alkaline solution of the leuco base of the dyestufl containing a water soluble organic substance acting as a.solvent for the salts of the leuco base of the dyestufl in a proportion of at least 20% by weight of the dyeing baths, and producing the dyestui! by oxidation on the fibres. g

2. A vat process for dyeing fibrous materials II with vat dyestufis comprising immersing the said materials in an alkaline solution of the leuco base of the dyestuil containing an alcohol having not more than five carbon atoms in the molecule in a proportion of at least 20% by weight of the dyeing baths, and producing the dyestufi by oxidation on the fibres.

3. A vat process for dyeing fibrous materials with vat dyestufls comprising immersing the said materials in an alkaline solution of the leuco base of the dyestufl containing ethanol in a proportion of at least 20% by weight of the dyeing baths,

and producing the dyestufl by oxidation on the 

